airport email setup

I have a desktop G5 and SBC DSL. I have successfully added the Airport extreme card and can access the internet from my powerbook. I CAN'T access email, however, either my SBC account or my AOL account. I can't even get to the screen where you enter your email. I think it must be a simple setting somewhere, but I can't figure it out. I've read about changing the modem to bridge mode...is this necessary if I'm able to access the internet (just not email)? Thanks for any help. Chris